Optical scope system for capturing an image of a scene

ABSTRACT

An optical device for capturing an image of a scene, the optical device comprising: a plurality of image sensors each operable to capture a respective initial image of the scene; a lens arrangement operable to receive light from the scene and to form each initial image on each respective image sensor, each image sensor being located at a different respective distance from the lens arrangement; and an image processor operable to generate the captured image of the scene on the basis of image data from one or more of the captured initial images.

BACKGROUND Field of the Disclosure

The present disclosure relates to a capturing an image of a scene. Inparticular, the present disclosure relates to capturing an image in anoptical scope system.

Description of the Related Art

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thebackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentdisclosure.

A problem with certain image capture devices such as those used inindustrial instruments (such as industrial endoscopes) or medicalinstruments (such as medical endoscopes) is the limited depth of fieldat which high spatial frequencies can be obtained in order to capture asufficiently sharp image. In order to improve the depth of field, thesize of the aperture through which light travels to form the image to becaptured can be reduced (increasing the so-called F number (F #) of theimage capture device). This leads to a larger depth of field, but, inturn, reduces the resolution/in-focus sharpness (due to diffraction) andincreases the noise of the captured image (due to there being lessreceived light and thus a reduced signal to noise ratio). In otherwords, there is a trade off between having a larger depth of field andhaving greater in-focus sharpness and low noise images.

Furthermore, as the form factor of such image capture devices is reduced(for example, to allow smaller form factor endoscopes), thus requiringimage capture sensors with smaller pixel sizes, the problems of thisapproach are set to get worse.

Moreover, in many endoscope applications such as surgical endoscopy orindustrial endoscopy, high resolution images such as 4K, 8K or the likeare also desired. This means that the imager becomes larger and so thereis a trade-off required between the size of imager and the depth offocus, In other words, a problem exists of how to provide an extendeddepth of field when high resolution images (such as those provided usinglarger imagers) are required.

It is an aim of the present disclosure to address at least one of theseproblems.

SUMMARY

The present technique provides an optical scope system for capturing animage of a scene, the optical device comprising: a plurality of imagesensors each operable to capture a respective initial image of thescene; a lens arrangement operable to receive light from the scene andto form each initial image on each respective image sensor, each imagesensor being located at a different respective distance from the lensarrangement; and an image processor operable to generate the capturedimage of the scene on the basis of image data from one or more of thecaptured initial images.

This arrangement is advantageous because an image is produced that hasan improved depth of field for a given resolution/in-focus sharpness ofimage.

The present technique also provides a method of capturing an image of ascene, the method comprising: capturing a plurality of initial images ofthe scene, each initial image of the scene being captured using arespective one of a plurality of image sensors, wherein each imagesensor is located at a different respective distance from a lensarrangement operable to receive light from the scene and to form eachinitial image on each respective image sensor; and generating thecaptured image of the scene on the basis of image data from one or moreof the captured initial images.

The foregoing paragraphs have been provided by way of generalintroduction, and are not intended to limit the scope of the followingclaims. The described embodiments, together with further advantages,will be best understood by reference to the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIGS. 1A and 1B show an optical scope system according to an embodimentof the present technique;

FIG. 2 shows an example associated with the optical device; and

FIG. 3 shows a flow chart schematically illustrating a process accordingto an embodiment of the present technique.

DESCRIPTION OF THE EMBODIMENTS

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views.

FIGS. 1A and 1B show an endoscope system 800 for capturing an image ofthe scene 101 according to an embodiment of the present technique. Theendoscope system 800 is an example of an optical scope system andcomprises an image sensor 802, a lens arrangement 104 (this being anarrangement of one or more lenses and being camera adapter optics, alsoknown as adapting imaging optics, in this embodiment), an imageprocessor 900 and an output unit 904. The operation of each of the imageprocessor 900 and output unit 904 is controlled by a controller 902. Theimage sensor 802 and the lens arrangement 104 may form part of a camerahead and the image processor 900 and the output unit 904 may form partof a camera control unit.

In operation, the lens arrangement 104 receives light from the scene andforms a plurality of initial images of the scene at the image sensor 802using the received light. The image sensor 802 then captures eachinitial image of the scene (that is, it captures each initial image ofthe scene as an electronic image). These electronic images are thenprocessed by the image processor 900 so as to form a final image of thescene on the basis of image data from one or more of the capturedinitial images. The final image of the scene is then output for displayand/or storage by the output unit 904.

In this particular embodiment, the light from the scene used to form thecaptured image is received from a medical instrument (in this example, amedical endoscope 114, such as a surgical endoscope). That is, the lensarrangement 104 receives light from the scene captured by the medicalinstrument and forms the initial images of the scene at the image sensorusing this received light. It will be appreciated, however, that lightfrom the scene may be received from any other type of instrument, aslong as the light is focussed by the lens arrangement 104 at the imagesensor 802. An example of another type of instrument is an industrialinstrument such as an industrial endoscope. In the example of FIG. 1A,the instrument is a medical endoscope 114. Light from the scene entersan entrance pupil at a distal end 116 of the medical endoscope, travelsdown one or more optical fibres 117 of the endoscope, and exits theendoscope through an exit pupil at the proximal end 118 of theendoscope. This light is then received by the lens arrangement 104 and aplurality of initial images are formed at the image sensor 802.

The image sensor 802 of the endoscope system 800 comprises a pluralityof image sensors 102A, 102B and 102C (each image sensor being a chargedcoupled device (CCD), complementary metal oxide semiconductor (CMOS) orOrganic CMOS image sensor, for example). Each of the plurality of imagesensors is operable to capture a respective one of the initial images ofthe scene. That is, the lens arrangement 104 operable to receive lightfrom the scene and to form each initial image on a respective one of theimage sensors 102A, 102B and 102C. Each image sensor is located at adifferent respective distance from the lens arrangement so that thein-focus position in the scene is different for each initial image. Inthe example of FIG. 1B, the image sensor 102A is located at a distanceD₁ from the lens arrangement, the image sensor 102B is located at adistance D₂ from the lens arrangement, and the image sensor 102C islocated at a distance D₃ from the lens arrangement, wherein D₁≠D₂≠D₃.This means that each object in the scene is in focus in different one ofthe captured initial images, depending on its object distance in thescene. In the example of FIG. 1B, each of the plurality of image sensorsis located along a different respective optical path with respect to thelens arrangement. This is enabled by an arrangement of prisms 906A, 906Band 906C, which act to split beams of light received from the lensarrangement 104 along a plurality of optical paths. Each image sensor isthen placed along a respective one of the optical paths at theappropriate distance from the lens arrangement. It will be appreciatedthat any suitable method of splitting received beams of light into aplurality of beams following different optical paths could be used inthe lens 802, as will be appreciated by the skilled person.

Once each initial image has been captured, the image processor 900determines an image sharpness level for corresponding portions of eachof the captured initial images. The image processor 900 then determinesthe highest one of the determined image sharpness levels and generates,on the basis of image data from each of the captured initial images, thefinal image of the scene so that a portion of the final image of thescene corresponding to the corresponding portions of each of thecaptured initial images has a sharpness level equal to the determinedhighest image sharpness level.

Such an arrangement is exemplified with reference to FIG. 2, in whichthree initial images of a scene 1000A, 1000B and 1000C are used togenerate a final image of the scene 1000. It can be seen that thein-focus position of each of the initial images 1000A, 1000B and 1000Cis different, as will occur when each of the initial images is capturedby a different respective image sensor positioned at a differentrespective distance from the lens arrangement 104.

Each of the initial images and final image is divided into 9 portions asindicated by the grids 1001A, 1001B, 1001C and 1001 marked on eachimage. Corresponding portions of the images are those portions appearingat the same location in each image. Thus, for example, portion 1002A inimage 1000A, portion 1002B in image 1000B, portion 1002C in image 1000Cand portion 1002 in image 1000 are corresponding portions because eachof them is the top right portion for its respective image. Similarly,portion 1006A in image 1000A, portion 1006B in image 1000B, portion1006C in image 1000C and portion 1006 in image 1000 are correspondingportions because each of them is the bottom right portion for itsrespective image.

Due to the different in-focus positions of each initial image, a firstobject appearing to be in focus in a first portion of one of the initialimages will be out of focus in the corresponding portions of the otherinitial images. On the other hand, a second object appearing to be outof focus in a second portion of the one of the initial images will be infocus in the corresponding portion of one of the other initial images. Afinal image in which both the first and second objects appear to be infocus can therefore be generated on the basis of the first portion ofthe initial image in which the first object appears to be in focus andon the basis of the second portion of the initial image in which thesecond object appears to be in focus. Using this principle, a finalimage in which all objects in the image (which appear to be in focus inone of the initial images) appear to be in focus may be generated by theimage processor 900. It is noted that, in this description, an objectwhich appears to be more in focus may be described as appearing sharper,where as an object which appears to be less in focus may be described asappearing less sharp.

This is exemplified in FIG. 2, in which portion 1006A of image 1000A hasthe sharpest overall focus (compared to portion 1006B of image 1000B andportion 1006C of image 1000C), portion 1004B of image 1000B has thesharpest focus (compared to portion 1004A of image 1000A and portion1004C of image 1000C) and portion 1002C of image 1000C has the sharpestfocus (compared to portion 1002A of image 1000A and portion 1002B ofimage 1000B). Portion 1006 of final image 1000 is therefore based on theimage sharpness level of portion 1006A of image 1000A. Similarly,portion 1004 of final image 1000 is based on the image sharpness levelof portion 1004B of image 1000B, and portion 1002 of final image 1000 isbased on the image sharpness level of portion 1002C of image 1000C. Eachportion of the final image 1000 is therefore generated on the basis ofthe corresponding portion of the one of the initial images with thehighest image sharpness level for that portion. This allows the finalimage to have a large perceived depth of field, even though each initialimage may have a shallow depth of field. A larger aperture (smaller F #)may therefore be used (thus allowing increased in-focus sharpness(resolution) of the captured image and reduced image noise) whilst theproblem of reduced depth of field resulting from using a larger apertureis alleviated.

In the example of FIG. 2, each initial image is divided into only 9portions in this example for the sake of simplicity. In reality,however, it will be appreciated that there will be a much greater numberof smaller portions so that all objects within each image portion are atsubstantially the same object distance. This helps reduce the risk of asingle image portion comprising captured objects of significantlydifferent object distance (in this case, even the sharpest image portionmay contain out of focus details, resulting in a reduction in quality ofthe resulting final image). It will be appreciated that the smallestsize of an image portion is limited by the number of pixels of eachimage sensor required in order to determine sharpness information forthat image portion.

This determination of sharpness levels can be performed by partial imageblock (comprised of a block of pixels which form a sub-region of theimage) or based on pixel by pixel basis. If the system applies pixel bypixel basis transportation, the quality of image is improved on a pixelby pixel basis. However, if the system applies determining sharpnesslevel for each sub-region, calculation cost will be reduced compared tothe pixel by pixel basis

In a first variant of the present technique, each of the image sensorscaptures light using primary colours, namely each of red, green and blue(RGB) colour channels (for example, using an RGB Bayer array). The imageprocessor 900 then generates each portion of the final image of thescene on the basis of the one of the corresponding portions the initialimages which has the highest image sharpness level. In one example, themeasurement of the sharpness of each portion of each initial imageoccurs before demosaicing of the image. The demosaicing may then becarried out after the appropriate portions of the initial images havebeen combined in order to generate the final image.

In a second variant of the present technique, each of the image sensorscaptures light using a different respective one of red, green and blue(RGB) colour channels (so that, for example, image sensor 102A capturesred light, image sensor 102B captures green light and image sensor 102Ccaptures blue light). The image processor 900 then generates eachportion of the final image of the scene by transporting the imagesharpness level of the corresponding portion of the initial image withthe highest measured image sharpness level to the corresponding portionsof the other initial images, and combining the corresponding portion ofthe initial image which has the highest image sharpness level with thecorresponding portions of the other initial images to which the measuredhighest image sharpness level has been transported.

This is advantageous because as the sharpness levels are different amongRGB, this system can obtain the best sharpness values and provide thisvalue to the other colour signals. This provides a higher qualityresultant image. Also, this arrangement is easy to arrange using 3CMOSsensor systems.

As a further variant of the present technique, the system may have aplurality of image sensors (for example, more than one, two or eventhree). In addition to RGB colour, further sensor for infrared (IR) orNear-Infrared (NIR) wavelength may be arranged. (for example, see themultichannel camera produced by Optec S.p.A described athttp://www.optec.eu/en/telecamere_multicanale/telecamere_multicanale.asp)This NIR wavelength band is useful for fluorescence biomedical imagingor imaging vessels with more perceivable colour.

It is noted that, with the above-mentioned variants, the determinationof the sharpness level of each portion of the initial images may bedetermined using a suitable sharpness measurement technique, as is knownin the art. Furthermore, the transport of a measured sharpness level ofa portion of a first initial image to a corresponding portion of asecond initial image may be carried out using a suitable sharpnesstransport technique, as is known in the art.

As shown in FIG. 1B, the image sensor 802 may comprise a plurality ofimage sensor adjustment devices 901A, 901B and 901C. Each image sensoradjustment device is operable to adjust the distance of a respective oneof the image sensors from the lens arrangement. The controller 902 isoperable to control each of the image sensor adjustment devices toadjust the distance of each respective image sensor from the lensarrangement based on the optical properties of the instrument (such asendoscope 114) via which light is received, thus helping to ensuresufficient depth of field extension for a variety of differentinstruments. Such an arrangement allows, for example, the distance D₁,D₂ and D₃ of each respective image sensor from the lens arrangement 104to be adjusted in advance based on the optical properties of theinstrument to be used so as to achieve an optimal set of distances D₁,D₂ and D₃. An optimal set of distances may be determined by, forexample, the set of distances which maximise the depth of field of eachinitial image. In an embodiment, each image sensor is mounted on arespective one of the image sensor adjustment devices. Each image sensoradjustment device comprises an electro-mechanical actuator or the like(not shown) in order to adjust the position of its respective sensor. Assuch, the appropriate distances are adjusted depending on the types ofscopes attached to the instrument interface. Hence, image quality offinal image (i.e. extended depth of focus) is achieved.

The controller 902 may control the position of the image sensors to beadjusted on the basis of, for example, information received directlyfrom the instrument (such as endoscope 114) attached to the opticaldevice 800 via instrument interface 910 or from information receivedfrom a user of the optical device 800 via user interface 912. It isnoted that the optical device 800 may have one or both of the instrumentinterface 910 and user interface 912.

This instrument interface arrangement is advantageous it this is usedfor an optical scope system, such as an endoscope system as theendoscope system is generally compatible for various types of scopes(different diameters, direct-view or oblique view endoscopes).

The instrument interface 910 may be any suitable interface via which theoptical device 800 can receive information with the instrument (such asendoscope 114) to which it is attached. In one variant, the instrument(such as endoscope 114) attached to the endoscope system 800 has acorresponding instrument interface together with a suitable controllerand storage unit for storing information which, when received by thecontroller 902, allows the controller 902 to determine the image sensordistances to be used with the instrument. Such an arrangement isexemplified in in FIGS. 1A and 1B, which shows how a coupling portion120 of the endoscope 114 for physically coupling the endoscope 114 tothe endoscope system 800 comprises an instrument interface 122,controller 124 and storage unit 126. Information on the basis of whichthe controller 902 can determine the image sensor distances D₁, D₂ andD₃ to be used with the endoscope 114 is stored in the storage unit 126.When the endoscope 114 and optical device 800 are physically coupledtogether, the instrument interface 122 of the endoscope and theinstrument interface 910 of the optical device are in sufficientproximity for information to be exchanged between them. The controller124 of the endoscope 114 thus controls the information stored in thestorage unit 126 to be transmitted to the controller 902 of the opticaldevice via the instrument interfaces 122 and 912. The instrumentinterfaces may exchange information using any suitable technique, suchas via Bluetooth®, Wi-Fi® or Near Field Communication (NFC), forexample, or via a suitable physical connection such as electricalcontact. In an alternative variant, the instrument does not have acorresponding instrument interface, but, rather, has suitable markingswhich are detectable by the instrument interface 910 of the endoscopesystem 800. In this case, the information on the basis of which thecontroller 902 can determine the image sensor distances to be used withthe instrument is indicated by the markings. The markings may comprise,for example, a barcode, Quick Response (QR) code or the like and theinstrument interface 910 of the optical device 800 may be a barcodereader, QR code reader or other suitable reader.

The user interface 912 may be any suitable interface for allowing a userto provide information to the optical device 800 for use by thecontroller 902 in determining the image sensor distances to be used withthe instrument. For example, the user interface 912 may comprise one ormore of a touch screen, keyboard, various control buttons, a gesturerecognition system, a speech recognition system, or the like.

The information provided to the controller 902 via the instrumentinterface 910 or user interface 912 may be any suitable informationwhich allows the controller 902 to determine the image sensor distancesto be used with the instrument. For example, the information maycomprise the image sensor distances D₁, D₂ and D₃ themselves or maycomprise one or more optical properties of the instrument so as to allowthe controller 902 to calculate the image sensor distances D₁, D₂ andD₃. Alternatively, the information may simply identify the particularinstrument (for example, via a model number or serial number of thelike), and the controller 902 may then look up the instrument in asuitable database in order to obtain the image sensor distances or oneor more optical properties for calculating the image sensor distancesassociated with that instrument. The database may be stored in a storageunit 914 of the optical device 800 in advance. Alternatively, thedatabase may be stored at a remote location on a network (such as theinternet), which the controller 902 is able to access via networkinterface 916. The network interface 916 may be any suitable interfacesuch as a Wi-Fi® or Ethernet interface, for example. The database,whether stored in the storage unit 914 or at a remote location may beupdatable. This allows information to be added to the database for newlyavailable instruments which are compatible with the endoscope system800, thus allowing suitable image sensor distances to be determined forsuch newly available instruments. This allows the endoscope to bechanged more quickly which is important in an industrial or medicalsetting.

FIG. 3 shows a flow chart schematically illustrating a process accordingto an embodiment of the present technique. The process starts at step1100. At step 1102, the controller 902 controls the plurality of imagesensors 102A, 102B and 102C to capture a plurality of initial images ofthe scene. Each initial image of the scene is captured using arespective one of the plurality of image sensors. Each image sensor islocated at a different respective distance from the lens arrangement 104operable to receive light from the scene and to form each initial imageon each respective image sensor. At step 1104, the controller 902controls the image processor 900 to determine an image sharpness levelfor corresponding portions of each of the captured initial images and todetermining the highest one of the determined image sharpness levels. Atstep 1106, the controller 902 controls the image processor 900 togenerate, on the basis of image data from each of the captured initialimages, the captured image of the scene so that a portion of thecaptured image of the scene corresponding to the corresponding portionsof each of the captured initial images has a sharpness level equal tothe determined highest image sharpness level. The process then ends atstep 1108.

Although the foregoing has described the optical device in the contextof instruments (either medical or industrial, for example), thedisclosure is not so limited. For example, the optical device may beused in other devices such as cameras (either still cameras or videocameras) or the like. Also the scope described here is not limited to beinserted into a body (i.e. endoscope), and can be used for microscope orexoscope or the other types of optical scope.

Various embodiments of the present disclosure are defined by thefollowing numbered clauses:

1. An optical scope system (800) for capturing an image of a scene, theoptical device comprising:

-   -   a plurality of image sensors (102A-102C) each operable to        capture a respective initial image of the scene;    -   a lens arrangement (104) operable to receive light from the        scene and to form each initial image on each respective image        sensor, each image sensor being located at a different        respective distance from the lens arrangement; and    -   an image processor (900) operable to generate the captured image        of the scene on the basis of image data from one or more of the        captured initial images.

2. The optical scope system according to clause 1, wherein the imageprocessor is operable to:

-   -   determine an image sharpness level for corresponding portions of        each of the captured initial images;    -   determine the highest one of the determined image sharpness        levels; and    -   generate, on the basis of image data from each of the captured        initial images, the captured image of the scene so that a        portion of the captured image of the scene corresponding to the        corresponding portions of each of the captured initial images        has a sharpness level equal to the determined highest image        sharpness level.

3. The optical scope system according to clause 2, wherein:

-   -   each of the image sensors is operable to capture light using        each of red, green and blue (RGB) colour channels; and    -   the image processor is operable to generate the portion of the        captured image of the scene corresponding to the corresponding        portions the captured initial images on the basis of the one of        the corresponding portions of the captured initial images which        has the determined highest image sharpness level.

This is advantageous because as the sharpness levels are different amongRGB, this system can obtain the best sharpness values and provide thisvalue to the other colour signals. This provides a higher qualityresultant image. Also, this arrangement is easy to arrange using 3CMOSsensor systems.

4. The optical scope system according to clause 2, wherein:

-   -   each of the image sensors is operable to capture light using a        different respective one of red, green and blue (RGB) colour        channels; and    -   the image processor is operable to generate the portion of the        captured image of the scene corresponding to the corresponding        portions of the captured initial images by:    -   transporting the image sharpness level of the one of the        corresponding portions of the captured initial images which has        the determined highest image sharpness level to the other        corresponding portions of the captured initial images; and    -   combining the one of the corresponding portions of the captured        initial images which has the determined highest image sharpness        level with the other corresponding portions of the captured        initial images to which the determined highest image sharpness        level has been transported.

5. The optical scope system according to any preceding clause, whereineach of the plurality of image sensors is located along a differentrespective optical path with respect to the lens arrangement.

This allows that the system to capture multiple differently focusedimages simultaneously.

6. The optical scope system according to any preceding clause, whereinthe lens arrangement is operable to receive light from the scenecaptured by an optical instrument and to form the initial image of thescene on each image sensor using the received light, wherein thedistance of each respective image sensor from the lens arrangement isdetermined on the basis of one or more characteristics of the opticalinstrument.

7. The optical scope system according to clause 6, comprising aplurality of image sensor adjustment devices (901A-901C) each operableto adjust the distance of a respective one of the image sensors from thelens arrangement.

This allows the distances between sensors and object to be adjustable.

8. The optical scope system according to clause 7, comprising:

-   -   a user interface (912) operable to receive information from a        user for determining the distance of each respective image        sensor from the lens arrangement; and    -   a controller (902) operable to control the image sensor        adjustment devices to adjust the distance of each respective        image sensor from the lens arrangement on the basis the received        information.

9. The optical scope system according to clause 7, comprising:

-   -   an instrument interface (122) operable to receive information        from the optical instrument for determining the distance of each        respective image sensor from the lens arrangement; and    -   a controller (902) operable to control the image sensor        adjustment devices to adjust the distance of each respective        image sensor from the lens arrangement on the basis the received        information.

10. The optical scope system according to clause 8 or 9, wherein theinformation for determining the distance of each respective image sensorfrom the lens arrangement comprises (a) the distance of each respectiveimage sensor from the lens arrangement, (b) one or more opticalproperties of the optical instrument on the basis of which thecontroller is configured to calculate the distance of each respectiveimage sensor from the lens arrangement, or (c) an identifier of theoptical instrument on the basis of which the controller is configured toconsult a database in order to obtain the distance of each respectiveimage sensor from the lens arrangement or the one or more opticalproperties of the optical instrument for calculating the distance ofeach respective image sensor from the lens arrangement.

11. The optical scope system according to any one of clauses 6 to 10,wherein the optical instrument is an endoscope.

12. The optical scope system according to clause 11, wherein theendoscope is a medical endoscope.

This is particularly advantageous because in the field of medicalendoscopy, the requirement for high resolution images with a long depthof field is high.

13. An endoscopic system comprising an optical scope system according toany one of clauses 6 to 10 and an optical instrument configured tocapture light from the scene for use by the lens arrangement of theoptical device in forming an initial image of the scene on each imagesensor of the optical device.

14. A method of capturing an image of a scene in an optical scopesystem, the method comprising:

-   -   capturing a plurality of initial images of the scene, each        initial image of the scene being captured using a respective one        of a plurality of image sensors, wherein each image sensor is        located at a different respective distance from a lens        arrangement operable to receive light from the scene and to form        each initial image on each respective image sensor; and    -   generating the captured image of the scene on the basis of image        data from one or more of the captured initial images.

15. A recording medium storing a computer program for controlling acomputer to perform a method according to clause 14.

16. An optical scope system (800) for capturing an image of a scene, theoptical device comprising:

-   -   means operable to capture a respective initial image of the        scene;    -   means operable to receive light from the scene and to form each        initial image on each respective image sensor, each image sensor        being located at a different respective distance from the lens        arrangement; and

means operable to generate the captured image of the scene on the basisof image data from one or more of the captured initial images.

Obviously, numerous modifications and variations of the presentdisclosure are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, thedisclosure may be practiced otherwise than as specifically describedherein.

In so far as embodiments of the disclosure have been described as beingimplemented, at least in part, by software-controlled data processingapparatus, it will be appreciated that a non-transitory machine-readablemedium carrying such software, such as an optical disk, a magnetic disk,semiconductor memory or the like, is also considered to represent anembodiment of the present disclosure.

It will be appreciated that the above description for clarity hasdescribed embodiments with reference to different functional units,circuitry and/or processors. However, it will be apparent that anysuitable distribution of functionality between different functionalunits, circuitry and/or processors may be used without detracting fromthe embodiments.

Described embodiments may be implemented in any suitable form includinghardware, software, firmware or any combination of these. Describedembodiments may optionally be implemented at least partly as computersoftware running on one or more data processors and/or digital signalprocessors. The elements and components of any embodiment may bephysically, functionally and logically implemented in any suitable way.Indeed the functionality may be implemented in a single unit, in aplurality of units or as part of other functional units. As such, thedisclosed embodiments may be implemented in a single unit or may bephysically and functionally distributed between different units,circuitry and/or processors.

Although the present disclosure has been described in connection withsome embodiments, it is not intended to be limited to the specific formset forth herein. Additionally, although a feature may appear to bedescribed in connection with particular embodiments, one skilled in theart would recognize that various features of the described embodimentsmay be combined in any manner suitable to implement the technique.

1. An optical scope system for capturing an image of a scene, theendoscope system comprising: a plurality of image sensors each operableto capture a respective initial image of the scene; a lens arrangementoperable to receive light from the scene and to form each initial imageon each respective image sensor, each image sensor being located at adifferent respective distance from the lens arrangement; and an imageprocessor operable to generate the captured image of the scene on thebasis of image data from one or more of the captured initial images. 2.The optical scope system according to claim 1, wherein the imageprocessor is operable to: determine an image sharpness level forcorresponding portions of each of the captured initial images; determinethe highest one of the determined image sharpness levels; and generate,on the basis of image data from each of the captured initial images, thecaptured image of the scene so that a portion of the captured image ofthe scene corresponding to the corresponding portions of each of thecaptured initial images has a sharpness level equal to the determinedhighest image sharpness level.
 3. The optical scope system according toclaim 2, wherein: each of the image sensors is operable to capture lightusing each of red, green and blue (RGB) colour channels; and the imageprocessor is operable to generate the portion of the captured image ofthe scene corresponding to the corresponding portions the capturedinitial images on the basis of the one of the corresponding portions ofthe captured initial images which has the determined highest imagesharpness level.
 4. The optical scope system according to claim 2,wherein: each of the image sensors is operable to capture light using adifferent respective one of red, green and blue (RGB) colour channels;and the image processor is operable to generate the portion of thecaptured image of the scene corresponding to the corresponding portionsof the captured initial images by: transporting the image sharpnesslevel of the one of the corresponding portions of the captured initialimages which has the determined highest image sharpness level to theother corresponding portions of the captured initial images; andcombining the one of the corresponding portions of the captured initialimages which has the determined highest image sharpness level with theother corresponding portions of the captured initial images to which thedetermined highest image sharpness level has been transported.
 5. Theoptical scope system according to claim 1, wherein each of the pluralityof image sensors is located along a different respective optical pathwith respect to the lens arrangement.
 6. The optical scope systemaccording to claim 1, wherein the lens arrangement is operable toreceive light from the scene captured by an optical instrument and toform the initial image of the scene on each image sensor using thereceived light, wherein the distance of each respective image sensorfrom the lens arrangement is determined on the basis of one or morecharacteristics of the optical instrument.
 7. The optical scope systemaccording to claim 6, comprising a plurality of image sensor adjustmentdevices each operable to adjust the distance of a respective one of theimage sensors from the lens arrangement.
 8. The optical scope systemaccording to claim 7, comprising: a user interface operable to receiveinformation from a user for determining the distance of each respectiveimage sensor from the lens arrangement; and a controller operable tocontrol the image sensor adjustment devices to adjust the distance ofeach respective image sensor from the lens arrangement on the basis thereceived information.
 9. The optical scope system according to claim 7,comprising: an instrument interface operable to receive information fromthe optical instrument for determining the distance of each respectiveimage sensor from the lens arrangement; and a controller operable tocontrol the image sensor adjustment devices to adjust the distance ofeach respective image sensor from the lens arrangement on the basis thereceived information.
 10. The optical scope system according to claim 9,wherein the information for determining the distance of each respectiveimage sensor from the lens arrangement comprises (a) the distance ofeach respective image sensor from the lens arrangement, (b) one or moreoptical properties of the optical instrument on the basis of which thecontroller is configured to calculate the distance of each respectiveimage sensor from the lens arrangement, or (c) an identifier of theoptical instrument on the basis of which the controller is configured toconsult a database in order to obtain the distance of each respectiveimage sensor from the lens arrangement or the one or more opticalproperties of the optical instrument for calculating the distance ofeach respective image sensor from the lens arrangement.
 11. The opticalscope system according to claim 6, wherein the optical instrument is anendoscope.
 12. The optical scope system according to claim 11, whereinthe endoscope is a medical endoscope.
 13. An endoscopic systemcomprising an optical scope system according to claim 6 and an opticalinstrument configured to capture light from the scene for use by thelens arrangement of the optical device in forming an initial image ofthe scene on each image sensor of the optical device.
 14. A method ofcapturing an image of a scene in an optical scope system, the methodcomprising: capturing a plurality of initial images of the scene, eachinitial image of the scene being captured using a respective one of aplurality of image sensors, wherein each image sensor is located at adifferent respective distance from a lens arrangement operable toreceive light from the scene and to form each initial image on eachrespective image sensor; and generating the captured image of the sceneon the basis of image data from one or more of the captured initialimages.
 15. A recording medium storing a computer program forcontrolling a computer to perform a method according to claim
 14. 16. Anoptical scope system for capturing an image of a scene comprising meansconfigured to perform a method according to claim 14.